Introduction:
The association between intimate partner violence (IPV) and depression has been well shown in cross-sectional studies. However, there has been little longitudinal evidence to establish causation.

Methods:
The Central Pennsylvania Women's Health Study (CePAWHS) is a longitudinal cohort of 1,420 childbearing-age adult women derived from a random digit dial telephone survey. Interviews conducted at baseline and 2-year follow-up included an extensive range of topics including recent intimate partner violence (IPV) and depressive symptoms. Recent IPV was defined by a positive response to any of 8-items assessing physical and sexual violence exposure in the past 12 months. Depressive symptomatology was defined using a dichotomized measure from a 6-item scale based on the Center for Epidemiologic Studies Depression Scale. We performed a 2-step multivariable logistic regression to study the association between recent IPV exposure at baseline and depressive symptoms at 6-month follow-up. In the first step, we controlled for depressive symptoms at baseline, perception of unfair treatment due to gender or race, self-reported health status, psychosocial stress, and sociodemographic characteristics (age, race/ethnicity, marital status, education, having kids at home, and household income); in the second step, we additionally entered covariates we hypothesized could mediate the association, specifically avoidance of binge drinking (an indicator of unhealthy coping), self-esteem, and social support.

Results:
Recent IPV was reported by 5% at baseline; high depressive symptoms were reported by 18% of women at follow-up. In the first step of the multivariable modeling, recent exposure to IPV at baseline was independently associated with depressive symptoms at follow-up (adjusted OR 2.19, 95% CI 1.22-3.91). Other predictors of depressive symptoms at the follow-up were baseline depressive symptoms (adjusted OR 4.08, 95% CI 2.93-5.67), perceived unfair treatment due to gender/race (adjusted OR 1.52, 95% CI 1.08-2.13), lower perceived overall health status (adjusted OR 1.55, 95% CI 1.14-2.11), and higher psychosocial stress (adjusted OR 1.50, 95% CI 1.09-2.07). Sociodemographic characteristics associated with depressive symptoms at follow-up were age over 35, high school education only or less, and lower household income. Inclusion of the mediating variables in the second step of the model indeed attenuated effect of IPV on future depressive symptoms (adjusted OR 1.72, 95% CI: 0.93- 3.16).

Conclusion:
The greater than doubled odds of having depressive symptoms two years after exposure to IPV provides further evidence that IPV results in future mental health problems. Higher social support and self-esteem mediates this association, suggesting that these psychosocial factors may enable women to better cope with the health consequences of IPV.